Stop mechanism for lifting-jacks



F. L. GORMLEY. j

. 1. 1380, 375, I tente ne7,1921.

. 3 SHEETS-SHEET l.

, F. L. GORMLEY.

STOP MECHANISM FOR LIFTING .JACKS.

APPLICATION FI'LED um.2o. |921.

1,380,375; Patentd June. 7, 1921.

3 SHEETS-SHEET 3.

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.FrlI. Gormleg b y Jay,

; UNITED stares FRANK I1. GORMLEY, OF'BROOKLINE, MASSACHUSETTS.

STOP MECHANISM FOR LIFTING-JACKS.

Specification of Letters Patent.

Patented June 7, 1921.

Application filed. January 20, 1921. Serial No. 438,540.

To all whom it may concern:

Be it known that I, FRANK L. GoRMLiiY, acitizen of the United States of America, and a resident of Brookline, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Stop Mechanism for Lifting-Jacks, of which the following is a specification.

' This invention relates'to stop mechanisms for lifting jacks and particularly that class of lifting jacks known as screw jacks.

The object of the invention is the production of a device of this character which will operate automatically to preventthe movable member of the jack from passing beyondthe point of safety. I

The invention consists of. certain novel.

, tion, one preferred form thereof is" illus trated in the drawings, this form having been found to ,glve satisfactory and reliable results although it is to be. understood that the various instrumentalities of which the invention consists can be variously arranged and organized and the invention is not limited to the precise arrangement and organization of these instrumentalities as herein shown and described except as required by the scope of the appended claims. UOfthe drawings--- Figure 1- represents a horizontal section of: a'portion of, a screw jack showing in plan a stop mechanism embodyingthe principles of the present invention. a

Fig. 2 represents a vertical section of the same on line 2, 2, on: Fig. 1. r 1

. Fig. 3 represents a horizontal section, similar to. Fig. 1, with the upper toothed plate removed.- Fig. 4 represents an inverted plan of the upper toothed plate.

Fig. 5 represents an elevationof the :up-

per end of-th'e standard and 'showingin elevation the toothed upper plate removed from coaction with the teeth formed upon or secured to the upper end of said sta dard, and Fig. 6 represents a vertical section of a lifting jack with theimproved stop mechanism applied thereto.

Similar characters indicate like parts throughout the several figures of the drawings.

In the drawings, 10 represents a suitable base supporting astationary standard-11 overthe outer periphery of which is fitted a movable sleeve 12, to the upper end of which is threaded a cap 13.

In .the upper end of the standard 11, is mounted a nut 14.- to which is threaded a lifting screw 15 having splined to its upper reduced end a bevel gear 16 with which meshes ,a bevel gear 17 formed upon or secured to a revoluble shaft or spindle 18, the outer end of which i providedwith a suitable operating mechanism 19 of any well known construction.

Between the upper face ofthe bevel gear 16 and the inner faceof the cap 13 are two annular plates 20, 21, between which are v interposed a V plurality of anti-friction members 22.

The movable member 12 isprovided on one side with a flanged projection 24 havplate 25 secured thereto by [gear wheel 29 having secured to one face thereof a pluralitv of pawls. 30 coacting with said ratchet wlieel27. I

Beneath the gear'wheel 29 is a revoluble shaft 35 having secured thereto a pinion 36 meshing with said gear 29 and driven thereby when the movable member 12 of the jack is being lowered. i

The shaft 35 hasalso secured thereto a worm wheel 37 which meshes with aworm 38 revoluble in'bearings in the bracket 39 secured tojthe inner face of theremovable plate 25. r a r 7 As thus far described, the lifting jack is the same as that shown in Patent No. 1.32%,345issued to me Dec. 9, 1919. The

worm 38 may have secured thereto any suit- I to the patent above referred to for av more complete description of the means of operating the ack.

It is obvious that some other form of actuating mechanism may be used equally as well as that shown in my earlier patent, the invention being adapted to beused on any form'of screw jack in which a sleeve moves endwise on a supporting standard.

The standard 11 is provided in its upper end; with two. cylindrical chambers 40 in the plate 42.

which is positioned the cylindrical extensions 41 of a. plate 42 disposed upon the standard 11; and having an opening therein through which 'theli'tting screw 15; extends.

Each fiyllllldflfifll extension 41 hasa cylindrical depression 43. therein. in 'which is mounted a helical spring 44. Each helical: spring surrounds a bolt threaded to the standard 11 and havin a head; 46 in a recess 47. in. the upper face or The head 46 forms shoulder tor the upper end of the spring 44; which spring of the screw 15 the vertical edges of said; teeth are in engagement and as a conse' tends tomove the plate downwardly and retain it under normal conditions in its lowermost position.

The plate 42 is provided with a plurality of ratchet teeth 48 engaging with a pluralityof teeth 49 formed upon an annular plate 50 secured to the upper end of the revoluble nut '14. I

Thenut 14 under abnormal conditions is freelyrevoluble about the axis of the standard 11 and in order .to reduce the friction when the'nut 14 is revolved said nut is mounted upon an anti-friction support consisting of two annular plates 51 and 52 with a plurality of balls or similar rolling members 53 interposed between said plates.

The ratchet teeth 48 and 49 are so con-- structedthat during the lifting movement safety the said shoulder will come into contact with the ends of the plate 42 and lift said plate against the tension of the springs until the teeth 48 and49 are disengaged. After these teeth 48 and 49 have been disengaged, the nut is freely revoluble and will rotate with the screw without imparting any upwardmovement to said screw.

As soon as the teeth 48 and 49 have become disengaged, the bottom wall of the depressions 47 will come into contact with the under faces of the heads 46 of the screws 45 and limit further upward movement of said plate 42.

As soon as the sleeve is permitted to lower under its load the springs 44 will operate and return the plate 42 to its normal position with the teeth 48 thereon in engagement with the teeth49,

This makes a very effective stop mechanism for lifting jacks which issimplein construction.

It has a particular advantage in being located within the sleeve 12 where it cannot be tampered with. i It is believed that the operation and many advantages of the invention will, be understood without further description.

Having thus described my-invention, I claimq p '1. In a lifting-jack a standard; a. nut therein normally locked: from rotation; a revoluble screw therein; a sleeve surroundingthe standard and movable endwise. with said screw; and means actuated by the movement of said sleeve for unlocking said nut and. permitting its: free rotation with said screw. 1 i

2. In. a liftingjaclga standard; a nut therein normally locked? from. rotationyantifriction members supporting said nut; a revoluble screw in said nut; a sleeve surrounding the standard and movable end-'- wise with said screw; and means actuated bythe movement of saidv sleeve for unlocking said nut and permitting its free rotation with said screw;

3. In a lifting jack a standard; a nut therein. normally locked from rotation; ratchet teeth on the upper end of said nut;

revoluble screw in said nut; a sleeve surrounding the standard and movable endwise with said screw; a non-revoluble plate provided with teeth adapted to coact with the teeth of said nut and provided with projections in the path of movement of shoulders on said sleeve; and means for normally retaining the two sets of teeth in'engagement. a

4. In a lifting j'ack;a standard; a nut therein normallylockedf-rom rotation; ratchet teeth on the upper end or said nut; a revoluble screw in said nut; asleeve surrounding the standard and movable end-' provided with teeth adapted to coact with the teeth of said nut and provided with projections in the path of movement of shoulders on said sleeve, said plate having depressions therein; headed bolts extending through said depressions and secured to the standard; and springs surrounding said bolts.

6. In a lifting jack, a standard having cylindrical chambers in the upper end thereof; a nut in said standard and revoluble therein; ratchet teeth on the upper end of said nut; a plate having ratchet teeth adapt-' ed to coact with the teeth of said nut and prevent the rotation of said nut; recessed projections on said plate positioned in said chambers; headed bolts extending through said projections and secured to said standard; springs surrounding said bolts; a revoluble screw in said nut; and a sleeve movable endwise with said screw and provided with a shoulder adapted to engage said plate and move it against the tension of said springs until the two sets of teeth are disengaged.

7. Ina lifting jack, 3, standard having cylindricalchambers in the upper end there of; a nutin said standard and revoluble therein; ratchet teeth on the upper end of said nut; a plate having ratchet teeth adapted to coact with the teeth of said nut and prevent the rotation of said nut; recessed projections on said plate positioned in said chambers; headed bolts extending through said projections and secured to said standard; springs surrounding said bolts; a revoluble screw in said nut; a sleeve movable endwise with said screw and provided with a shoulder adapted to engage said plate and move it against the tension of said springs until the two sets of teeth are disengaged; and means for limiting the upward movement of said plate.

8. In a lifting jack, a standard; a nut therein and freely revoluble; a revoluble screw in said nut; and means mounted on the upper end of said standard for normally preventing rotation of said nut and adapted to be actuated in the lifting operation at a predetermined time to release said nut and permit its rotation.

9. In a lifting jack, a standard; a nut therein and freely revoluble; a revoluble screw in said nut; a sleeve surrounding said standard and movable endwise with said screw; and means mounted on the upper end of said standard for normally preventing rotation of said nut and adapted to be actuated in the upward movement of said sleeve to release said nut and permit its rotation. v

10. In a lifting jack, a standard; a nut therein and freely revoluble; a revoluble screw in said nut; a sleeve surrounding said standard and movable endwise with said screw; means mounted on the upper end of said standard for normally preventing rotation of said nut and adapted to be actuated in the upward movement of said sleeve to release said nut and permit its rotation;

and means for preventing farther upward movement of said sleeve when the nut has been released.

Si ed by me at 294 Washington St, Boston, ass, this 18th day of January, 1921.

FRANK L. GORMLEY.

Witnesses :v

WALTER E. LOliIBARD, NATHAN CQLOMBABD. 

